This invention relates, generally, to the use and structure of removable electronic circuit cards having different mechanical and/or electrical interfaces, and, more specifically, to the use of non-volatile memory cards according to the related MultiMediaCard (xe2x80x9cMMCxe2x80x9d) and Secure Digital (xe2x80x9cSDxe2x80x9d) Memory Card interfaces and cards having an interface according to a standard of the International Organization for Standardization (xe2x80x9cISOxe2x80x9d) and the International Electrotechnical Commission (xe2x80x9cIECxe2x80x9d), an example being the ISO/IEC 7816 standard.
The physical and electrical specifications for the MMC are given in xe2x80x9cThe MultiMediaCard System Specificationxe2x80x9d that is updated and published from time-to-time by the MultiMediaCard Association (xe2x80x9cMMCAxe2x80x9d) of Cupertino, California. Versions 2.11 and 2.2 of that Specification, dated June 1999 and January 2000, respectively, are expressly incorporated herein by this reference. MMC products having varying storage capacity up to 64 megabytes in a single card are currently available from SanDisk Corporation of Sunnyvale, Calif., assignee of the present application. These products are described in a xe2x80x9cMultiMediaCard Product Manual,xe2x80x9d Revision 2, dated April 2000, published by SanDisk corporation, which Manual is expressly incorporated herein by this reference. Certain aspects of the electrical operation of the MMC products are also described in co-pending patent applications of Thomas N. Toombs and Micky Holtzman, Ser. Nos. 09/185,649 and 09/186,064, both filed Nov. 4, 1998, and assigned to SanDisk Corporation. The physical card structure and a method of manufacturing it are described in U.S. Pat. No. 6,040,622, assigned to SanDisk Corporation. Both of these applications and patent are also expressly incorporated herein by this reference.
The newer SD Card is similar to the MMC card, having the same size except for an increased thickness that accommodates an additional memory chip. A primary difference between them is that the SD Card includes additional data contacts in order to enable faster data transfer between the card and a host. The other contacts of the SD Card are the same as those of the MMC card in order that sockets designed to accept the SD Card will also accept the MMC card. The electrical interface with the SD card is further made to be, for the most part, backward compatible with the MMC product described in version 2.11 of its specification referenced above, in order that few changes to the operation of the host need be made in order to accommodate both types of card.
Cards made according to the ISO/IEC 7816 standard are of a different shape, have surface contacts in different positions, and a different electrical interface than the MMC and SD Cards. The ISO/IEC 7816 standard has the general title of xe2x80x9cIdentification cardsxe2x80x94Integrated Circuit(s) Cards with Contacts,xe2x80x9d and consists of parts 1-10 that carry individual dates from 1994 through 2000. This standard, copies of which are available from the ISO/IEC in Geneva, Switzerland, is expressly incorporated herein by this reference. ISO/IEC 7816 cards are particularly useful in applications where data must be stored in a secure manner that makes it extremely difficult or impossible for the data to be read in an unauthorized manner.
One general use of the small ISO/IEC 7816 cards is for security against the theft and/or unauthorized use of electronic systems, in which case the card stores a security code personal to the user or the electronic system. A radio installed in a vehicle is one type of electronic system, for example, where a security code personal to the radio needs to be input at times in order for the radio to operate. In one arrangement, circuitry within the radio is provided that renders it inoperable when battery power has be disconnected. Entry of a unique security code is then required to again allow the radio to operate. One way to deliver the security code is to store it on a small ISO/IEC 7816 card and provide a card slot in the radio into which the card is inserted. Circuits are included in the radio to read the code from the card, compare it with a unique code for the particular radio and, if the codes match, re-enable operation of the radio after the battery has been reconnected.
A single card receptacle of a host electronic system can interact with one or more removably insertable cards according to two or more different existing card standards that are incompatible with each other as to their physical card shapes, arrangements of external contacts and electrical signal interfaces. For example, some data, such as a unique security code, are readable by the system according to the ISO/IEC 7816 card standard that is best adapted to handle such data, and other data, such as user data or operating programs, are readable by the system according to either of the MMC or SD Card standards for which those standards have been designed. The present invention is not limited, however, to the use of any particular card standard or types of data stored according to existing card standards.
In one specific embodiment, the physical standards of one type of card are altered to conform to those of another type of card, and each type of card is then separately formed in a package that has the physical characteristics of the other type of card. For example, a card according to the ISO/IEC 7816 standard is physically altered to have the same shape and pin locations specified by either of the related MMC or SD Card standards, with the receptacle of the electronic system conforming to that card standard. The two or more cards are then accepted by a single receptacle of the electronic system.
In another specific embodiment, the functions according to two or more card standards are combined on a single card having the physical dimensions and electrical contact locations of one of those standards. For example, a card according to either of the related MMC or SD Card standards can be modified to include the circuitry of a card according to the ISO/IEC 7816 standard, with the two or more electrical functions of the different standards sharing a common set of card contacts.
There are many applications of these embodiments. For example, in a vehicle radio, a card receptacle is adapted to receive both a card containing a security code and a memory card containing data of music that may be reproduced through the vehicle""s audio system when enabled by the correct security code. In another example, a portable electronic device, such as a hand held computer, personal organizer, cellular telephone, or the like, has a card slot that receives a card including a part of a utilization program that changes from time-to-time, or data for use with a utilization program, in addition to receiving a card containing a security code that enables the utilization program to operate in the device. In a further example, a GPS receiver card slot receives a card containing a user security code to enable operation of the receiver and a card containing data that are used in the operation of the receiver to locate position and the like. In each case, the utilization data and the security code may alternately be contained on the same card.
In these applications, when separate cards are being used, the security code may be stored on a low capacity, relatively inexpensive memory card which the device owner would normally maintain separate from the electronic device in a safe place. A different one or more memory cards of the same type but of larger storage capacity are then used to store the associated data. Circuits within the electronic device distinguish the security code from the associated data when reading a card placed in its slot and use the data accordingly.